Last weekend Philadelphia celebrated the anniversary of Benjamin Franklin's electric kite experiment (in which he flew a kite during a thunderstorm and proved that lightning was a form of electricity). They did so despite the fact that many believe the experiment was a hoax... that it never happened. The Philadelphia Inquirer provides a summary of this debate.

The main proponent of the electric-kite-hoax theory is Tom Tucker, author of Bolt of Fate: Benjamin Franklin and his Electric Kite Hoax. (I noted the publication of his book back in 2003 when it first appeared in print.) Tucker points out that a) "Franklin did not publicize the kite flight until four months later, and then only with a passing mention in the Pennsylvania Gazette"; b) Franklin would have been very stupid to perform such an experiment because it could very easily have killed him; and c) Franklin was a known trickster and a great self-publicist who would not have been above taking credit for something he never did. Defenders of Franklin argue that all of Tucker's evidence is circumstantial. Personally, I'm inclined to believe the hoax theory. I think that Franklin would have been too smart to try such a deadly experiment. But, of course, it's the kind of thing historians can argue about until they're blue in the face. Ultimately there's no definitive evidence to prove that Franklin did or did not perform the experiment.

Update: Since Captain Al pointed out that the kite experiment wouldn't be deadly with some simple safety modifications, let me clarify exactly what Tucker's argument is. Tucker notes that Franklin had been sending the British Royal Society reports about his electricity experiments, but that these reports were being marginalized, mainly because the members of the RS regarded him as an uncouth American. So Tucker suggests that Franklin, frustrated at how he was being treated, sent the RS a report of the deadly electric kite experiment as a joke. It was basically the scientific equivalent of giving them the finger... suggesting that they go fly a kite in a thunderstorm. Franklin knew, and the RS members knew, that doing so could be fatal. But when the report reached France, people there took it seriously. So Franklin, knowing a good PR opportunity when he saw it, played along and began claiming that he really had done the experiment. That's the jist of Tucker's argument.

Mythbusters actually already did a test on this event. It's new enough that they're regularly repeating it. Conclusion? Didn't happen.

Posted by Bill on Wed Jun 21, 2006 at 05:35 AM

Saw the Mythbuster episode too. Conclusion, COULDN'T have happened. Not just because of the obvious details, but Mythbusters actually considered the details of the structure where the Ben Franklin experiment happened. ALL things considered, there is NO way the experiment could have happened...

Posted by Nettie in Perth, Western Australia on Wed Jun 21, 2006 at 07:28 AM

Yeah, but Mythbusters also said Archimedes' method of setting Roman ships on fire during the siege of Syracuse wasn't possible either. Yet not one, but two college student experiments proved *them* wrong!

I saw that show. They couldn't even build a working kite. I may be mistaken, but I do believe that kites have been flown by other people. It's a great show but they do take themselves a little too seriously.

Posted by Dave in Phx on Wed Jun 21, 2006 at 10:25 AM

I'm not familiar with the exact details of Franklin's alleged experiment, but it seems to me it wouldn't be dangerous as long as he wasn't physically holding the kite's tether. It could have been tied to a stake in the ground or a fence.

Frederick, all the college students prove was that a large number of people holding mirrors might eventually set fire to your boat.

This assumes that -

1) The defenders on the boat are taking no action to put out the fire (being surrounded by water and all).

2) The defenders are kind enough not to shoot dead all the people standing there holding mirrors.

3) The defenders are thoughtful enough to park their boat to make it easier for the mirrors to focus on them.

All in all, not very likely.

Posted by Charybdis in Hell on Wed Jun 21, 2006 at 10:39 AM

I should also point out that all the fan mirrors, save the one that tragically broke apart in transit, had a focal point of only a few feet. At that range a defender would just stab you with his sword.

Having said all this, I must also state that I'm well aware that Mythbusters is for entertainment only, and in almost no way is it real science. While I wish they would actually do a bit more work before reaching their conclusions, it's still an enjoyable show.

Posted by Charybdis in Hell on Wed Jun 21, 2006 at 10:42 AM

I posted an update clarifying Tucker's argument.

Posted by The Curator in San Diego on Wed Jun 21, 2006 at 03:43 PM

Charybdis said:
"I should also point out that all the fan mirrors, save the one that tragically broke apart in transit, had a focal point of only a few feet."

The mirrors needed for this really should be flat. In other words, they would have no focal length. It's the aim and placement of the people holding them that determines the location and heat intensity of the focal point.

I believe there was a short story by sci-fi guru Arthur C. Clarke that used this as a plot device. Unfortunately I can't remember the name of it. It was soccer match between two arch rival countries. The home team gave small 1 foot square mirrors to every fan in the stadium. When the referee made a bad call against the home team, fans were instructed to aim the reflection of the sun at him, just to be nasty.

However, when a particularily bad call was made, the entire stadium did this at once and it instantly vaporized the referee. So you see, it was the size and shape of the stadium, filled with fans holding mirrors, that made the focal point so hot. The idea setting a wooden ship on fire with this method seems plausible to me but in Archimedes's time, where would you get enough mirrors on short notice to accomplish this feat?

No no, Ben Franklin flew the kite as the storm was approaching. He felt little zaps and then packed up and left with his conclusion.

Posted by RedNeckOreo in a pickle on Wed Jun 21, 2006 at 07:18 PM

I'm with RedNeckOreo on this one.

In the history book I read, way back when, Franklin did his experiment while a thunderstorm was approaching, not actually in the lightning.

He also stood under the roof of an open shed and had a length of silk ribbon insulating him from the key and kite line. (The shed kept the rain of him and the ribbon, lowering the chance of them conducting.)

At least, that's the way I remember reading it.
He wasn't trying to prove that lightning was electricity directly, but that electric buildup in the storm caused lightning.

Of course, people DID try it during thunderstorms after Franklin, and they usually got zapped.

Oh, and to answer Captain Al; According to the legend, the Soldiers used their bronze faced shields, freshly polished, as the mirrors.

Posted by Captain DaFt on Wed Jun 21, 2006 at 09:09 PM

Captain Al: "A Slight Case of Sunstroke" is the story you were thinking of.

Aristophenes is the first person I can think of who came up with the idea of focusing the sun to use it as a weapon, mentioning it in The Clouds some two centuries before Archimedes. So the idea wasn't exactly new in Archimedes' time.

According to Dio Cassius and Plutarch and Galen and others, Archimedes supposedly got the Greek soldiers to polish the inside of their curved bronze shields, and then had them stand in a parabola pattern. This focused the sun on the ships' riggings (which would be very flammable and also hard to reach quickly to extinguish), and that caught the ships on fire.

Proklos supposedly copied Archimedes' idea in the early 6th Century AD, with similar results against Vitalianus' fleet at Constantinople (although according to Malalas, they used Greek fire instead of sunlight). There have also apparently been other tests over the years that used the same techniques and had similar successful results; LeClerc of pi fame did it in France in the 18th Century, and in the 1970's a Greek physicist got a bunch of volunteers to hold polished bronze shields and set fire to a wooden mock-up of a ship a good 50m away. So again, it seems at least possible for such a system to have been used on

None of which has anything to do with Ben Franklin, of course. While I don't see why it wasn't possible for him to do what he did, I have no way of knowing if he actually did it. I'm afraid that my Ouija board is broken.

Their's was done at 100 feet because they didn't have more room than that, but their calculations showed it could be done at a greater distance with either more mirrors or the same amount slightly concaved. Though still within bow range, it's hardly the stabbing range Charybdis cited.
As to Franklin, according to legend, he was assisted by his illegitamite son, William. He grew up to be a strong Loyalist, which eventually caused father and son to stop speaking to each other. Did William ever deny the experiment took place, or his participation?

The stabbing range I cited had to do with the fan designs from Mythbusters. For the full scale mockup I correctly suggested bow range.

Still, while it may have been possible to set fire to one ship, they'd have been moving to fast to burn an entire fleet before they landed.

As for Franklin, wouldn't the pre-storm charges simply have been static electricity? It was already well known that static electricity builds up prior to a storm. I was always taught that he was supposed to have proved that lightning was electricity, which would have required a lightning strike.

As far as hiding in a shed, wouldn't the rain have run down the string soaking the silk ribbon and his hand?

Posted by Charybdis in Hell on Thu Jun 22, 2006 at 10:41 AM

I'm with Charybdis on the Archimedes experiment. In the Mythbuster's experiment with MIT, they couldn't even get a flame (only smoking) while the boat was sitting still in the water. Imagine keeping all of the mirrors properly aligned on a moving target. Sounds too tough to be true.

Posted by dae dae on Thu Jun 22, 2006 at 01:49 PM

The Roman ships wouldn't have been able to land, though, Charybdis. They were attacking the Achradina sea wall, so they would have tied together pairs of quinquiremes and built seige towers on them, and then have slowly moved those into place. So there would have been ample chance for a little pyromania. Also, the seige lasted about two years, so there would have been plenty of time to fry ships.

But really, what matters is that it has been shown that the process could have worked. So this means that Mythbusters isn't all that reliable of a source.

Posted by Accipiter on Thu Jun 22, 2006 at 01:50 PM

Thanks to Captain DaFt and RedNeck Oreo for identifying the fallacies in the story.

It's an amusing little fancy; and if Franklin's experiment had occurred as most artists depicted it, it would indeed have to be either dangerously foolhardy or a hoax.
But that is not the whole nor the true story.
I heard many years ago that the whole Franklin/kite story was affected by a misunderstanding.
Most people, recalling the famous drawings, assume that Franklin was attempting to "fly the kite into lightning, and then capture the lightning charge in a key in a glass jar."
This would be terribly foolhardy, even if the kite-string were grounded and the kite-flier were insulated.
Far more likely, however, was that Franklin merely sent the kite up into a cloudy (not stormy) sky -- or likelier, a sky in which storm clouds were gathering but not yet storming.
Whenever there are clouds, there is a buildup of static electricity, due to updrafts and downdrafts associated with the movement of water droplets and air molecules in the clouds. This is mainly due to friction -- much the same way that glass rods were induced to become electrically charged by rubbing them with cloths. (The more energetic the updrafts, the stronger the charges generated; thus high-wind storms result in lightning, while calm-weather clouds don't.)
This electrical charge can be channeled down a string or wire, even with no actual lightning being present. (The air itself would be charged, and the string would carry the not-nearly-lightning-strength charge away to the ground.)
The charge could then be channeled into a leyden jar (a primitive early form of battery), which would prove that the forces that give rise to lightning are the same as electrical charges.
(The usual pictures drawn of the event are wrong on multiple points: Franklin would have been sheltered in a shed, not standing outside; he would have held the string not directly, but secondarily -- insulated by attaching a dry silk ribbon to it; the sky would not have lightning in it, as that would be too dangerous; and his son William would have been a young man of 21 at the time, not a little boy as usually depicted.)

To sum up: debunking the popular misconception of Franklin's experiment is fine --
as long as the mythbusters bother to then explain what the real experiment was, and the precautions taken.
They didn't do that, so it's a classic straw man argument.

All the best,
Peace & Love,
David

Posted by David Hecht in Miami, FL on Sat Jun 24, 2006 at 11:28 PM

Yes, RedNeckOreo, Mythbusters did not recreate the Ben Franklin experiment correctly. He flew the kite in stormy clouds not in an actual storm. He merely revealed that clouds carried a charge. If he would have flown the kite in an electrical storm he would have blown his arm off.

Posted by gnumber9 in North Carolina, USA on Sun Jul 16, 2006 at 12:20 AM

Benjamin Franklin DID NOT get his kite struck by lightning! He flew it in a thunderstorm and collected a charge on the string, then used it to make a small arc on the ground.

Posted by Ian on Sat Jul 29, 2006 at 04:16 PM

Any 80 meter HF ham operator can tell you that an unterminated long wire outside in the wind will produce a spark at times and will knock you on your butt if you're the closest path to ground. You don't need a kite, just a long wire or antenna.

The Mythbusters "busted" conclusion is wrong. If it was wet, Franklin's kite string would have conducted small amounts of electricity and functioned like a long-wire radio antenna. Currents would have been induced in the kite string by Hertzian waves generated by lightning in the storm. The kite string didn't "collect" static electricity from the air. Instead, Franklin's experiment functioned like a very crude radio wave detector. The radio waves detected were the same as the noise heard in AM radio broadcast channels during electrical storms. Franklin claimed to have actually run the experiment and I see no reason to dispute his claim. Franklin got electricity out of the air but not by the mechanism everybody assumes.

Posted by Virgil H. Soule in Walkersville, MD on Tue May 28, 2013 at 09:41 PM
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